Pub Date : 2023-04-17DOI: 10.15625/2525-2518/17489
Tien-Anh Nguyen, T. V. Nguyen, Duc-Tan Tran
Ocean radiation monitoring and warning systems are essential in monitoring radioactive species' contamination levels in an oceanic environment and predicting the radioactive materials propagation caused by nuclear incidents in a marine area. Since the Fukushima nuclear disaster, different types of mobile radiation monitoring devices have been investigated based on modern technologies in electronic – communication. Those types of equipment can directly measure the radioactive contamination in the ocean instead of the traditional laboratory method. This study presents a complete process of researching, designing, manufacturing, and integrating a mobile radiation monitoring system (MRMS) in the ocean. The integrated radiation sensor can both measure radiation dose rate and identify radioactive isotopes on a floating device. The measured data from the sensor is processed and displayed on the electronic block by developed software, or it can be transmitted directly to the mainland by one of three different communication devices. This prototype system is the first product in Vietnam in the development of the MRMS, which is highly promising in terms of performance, low cost, and maintenance.
{"title":"Investigation to design, fabricate, and integrate a mobile radiation monitoring system in ocean","authors":"Tien-Anh Nguyen, T. V. Nguyen, Duc-Tan Tran","doi":"10.15625/2525-2518/17489","DOIUrl":"https://doi.org/10.15625/2525-2518/17489","url":null,"abstract":"Ocean radiation monitoring and warning systems are essential in monitoring radioactive species' contamination levels in an oceanic environment and predicting the radioactive materials propagation caused by nuclear incidents in a marine area. Since the Fukushima nuclear disaster, different types of mobile radiation monitoring devices have been investigated based on modern technologies in electronic – communication. Those types of equipment can directly measure the radioactive contamination in the ocean instead of the traditional laboratory method. This study presents a complete process of researching, designing, manufacturing, and integrating a mobile radiation monitoring system (MRMS) in the ocean. The integrated radiation sensor can both measure radiation dose rate and identify radioactive isotopes on a floating device. The measured data from the sensor is processed and displayed on the electronic block by developed software, or it can be transmitted directly to the mainland by one of three different communication devices. This prototype system is the first product in Vietnam in the development of the MRMS, which is highly promising in terms of performance, low cost, and maintenance.","PeriodicalId":23553,"journal":{"name":"Vietnam Journal of Science and Technology","volume":"54 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74043235","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-17DOI: 10.15625/2525-2518/16667
T. Nhi, Ha Le Thi Thanh, Thien Do Truong
In this stuty, sea rough fish were hydrolyzed with alcalase/peptidase combined enzymes (EA/EP). Response surface methodology (RSM) was employed to optimize the EA/EP, hydrolysis time, hydrolysis temperature, and enzyme to substrate ratio (E/S) to obtain a high hydrolysis degree. The optimum RSM operating conditions were EA/EP of 2.9, temperature 55.8oC, incubation time of 4.9 h, and substrate concentration at 0.45 %. Under these conditions, DH value of 56.2 % was obtained. Raw materials proximate composition, amino acid content of the hydrolysate was also evaluated. The results indicated that sea rough fish contains potentially valuable fraction with high protein content and were successfully converted into hydrolysates rich in essential amino acids for potential recommendations in the supplementation of animal and human diets.
{"title":"Enzymatic hydrolysis of sea rough fish","authors":"T. Nhi, Ha Le Thi Thanh, Thien Do Truong","doi":"10.15625/2525-2518/16667","DOIUrl":"https://doi.org/10.15625/2525-2518/16667","url":null,"abstract":"In this stuty, sea rough fish were hydrolyzed with alcalase/peptidase combined enzymes (EA/EP). Response surface methodology (RSM) was employed to optimize the EA/EP, hydrolysis time, hydrolysis temperature, and enzyme to substrate ratio (E/S) to obtain a high hydrolysis degree. The optimum RSM operating conditions were EA/EP of 2.9, temperature 55.8oC, incubation time of 4.9 h, and substrate concentration at 0.45 %. Under these conditions, DH value of 56.2 % was obtained. Raw materials proximate composition, amino acid content of the hydrolysate was also evaluated. The results indicated that sea rough fish contains potentially valuable fraction with high protein content and were successfully converted into hydrolysates rich in essential amino acids for potential recommendations in the supplementation of animal and human diets.","PeriodicalId":23553,"journal":{"name":"Vietnam Journal of Science and Technology","volume":"30 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87944419","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-17DOI: 10.15625/2525-2518/16399
Thao Huynh Van, Huynh Cong Khanh, Nguyen Cong Thuan, Nguyen Duc Tai, Nguyen Van Cong
This study investigated the status, environmental health risks and assessed contaminant concentrations of waste gases and ambient air quality in traditional charcoal production kiln areas in Hau Giang province. In total, 284 charcoal producers, 160 charcoal workers and 160 neighbors were interviewed using structured questionnaires. Additionally, Carbon monoxide (CO), nitro dioxide (NO2), total suspended particles (TSP), and sulfur dioxide (SO2) from traditional kilns and ambient air samples were analyzed. The result show that the number of kilns owned by each charcoal producer was 3.13 kilns per household; of which the average volume of each kiln was 59.07 m3 kiln-1, with a yearling charcoal yield of around 80.71 ton kiln-1. The profitability of charcoal producers was annually approximately 133 million VND per household. Charcoal workers predominantly reported suffering from eye irritation issues (41.6%) whilst adjacent neighbors frequently experienced respiratory problems (87.5%). The interviewees obviously recognized the negative impacts of charcoal production activities on community health (63.1% respondents) and local fruit farmers (79.4% respondents), yet only the minority of residents (8.11% respondents) required a change from the current charcoal-based livelihood. The CO, TSP, and SO2 in waste gas compositions all exceeded the maximum permissive levels of the Vietnamese National Standard (QCVN 19:2009/BTNMT), while the air quality surpassed the safety level of TSP and SO2 (QCVN 05:2013/BTNMT). This indicates very high risk to those who are regularly exposed to the air pollutants. The study suggested that technological solutions and responsible policies should be enforced to promote the sustainability of charcoal production and minimize the negative impacts on human health and the environment.
{"title":"Social and environmental impacts of traditional charcoal production: a case study in Hau Giang province, Viet Nam","authors":"Thao Huynh Van, Huynh Cong Khanh, Nguyen Cong Thuan, Nguyen Duc Tai, Nguyen Van Cong","doi":"10.15625/2525-2518/16399","DOIUrl":"https://doi.org/10.15625/2525-2518/16399","url":null,"abstract":"This study investigated the status, environmental health risks and assessed contaminant concentrations of waste gases and ambient air quality in traditional charcoal production kiln areas in Hau Giang province. In total, 284 charcoal producers, 160 charcoal workers and 160 neighbors were interviewed using structured questionnaires. Additionally, Carbon monoxide (CO), nitro dioxide (NO2), total suspended particles (TSP), and sulfur dioxide (SO2) from traditional kilns and ambient air samples were analyzed. The result show that the number of kilns owned by each charcoal producer was 3.13 kilns per household; of which the average volume of each kiln was 59.07 m3 kiln-1, with a yearling charcoal yield of around 80.71 ton kiln-1. The profitability of charcoal producers was annually approximately 133 million VND per household. Charcoal workers predominantly reported suffering from eye irritation issues (41.6%) whilst adjacent neighbors frequently experienced respiratory problems (87.5%). The interviewees obviously recognized the negative impacts of charcoal production activities on community health (63.1% respondents) and local fruit farmers (79.4% respondents), yet only the minority of residents (8.11% respondents) required a change from the current charcoal-based livelihood. The CO, TSP, and SO2 in waste gas compositions all exceeded the maximum permissive levels of the Vietnamese National Standard (QCVN 19:2009/BTNMT), while the air quality surpassed the safety level of TSP and SO2 (QCVN 05:2013/BTNMT). This indicates very high risk to those who are regularly exposed to the air pollutants. The study suggested that technological solutions and responsible policies should be enforced to promote the sustainability of charcoal production and minimize the negative impacts on human health and the environment.","PeriodicalId":23553,"journal":{"name":"Vietnam Journal of Science and Technology","volume":"15 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90102088","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-17DOI: 10.15625/2525-2518/16791
Nguyen Thi Thanh Hai, Truong Anh Dung, Nguyen Thi Quy
In the current integration trend, high-tech agriculture is an inevitable direction for agricultural developing countries. In particular, hydroponics is a commonly used farming technique due to many advantages: no soil, space saving, no weeds, easy control of influencing factors, double yield. Hydroponic crop production systems are used worldwide to grow flowers, foliage, litter, and fruit and vegetable crops. Like other farming methods, hydroponics still has problems with pests and diseases that cause serious damage to the harvest that have not been completely resolved. One of the sources of pathogens is the hydroponic solution. Many methods to kill bacteria and fungi in hydroponic solutions have been studied. However, some methods gave low efficiency, others gave high efficiency but it caused secondary environmental pollution. Electrochemical activated solution (EAS), produced from dilute sodium chloride (NaCl) solution, has been wide known as a super disinfectant solution with high ability to kill most bacteria and fungi and is safe for humans. In this study we were forced on determine the ability to control pathogens in hydroponic solution of EAS, the effects of EAS on hydroponic solution properties and the growth of Brassica juncea in the mixed of EAS – hydroponic solution. Difference volume of EAS were added into hydroponic solutions and mixed for 30, 45, 60, 120 or 180 min. The most effective mixed solution (mixed ratio and time) was selected to apply to cultivate Brassica juncea. The results show that EAS has the ability to control pathogens in hydroponic solution very effectively, replacing other harmful chemicals. When increasing the volume EAS added (higher ACC of mixed solution) or the exposure time the TDS and ORP index of hydroponic solution were raised slightly while pH value was slightly dropped and the total coliform counts decreased significantly. The total coliform counts of mixed solutions reduced over the exposed time. However, the increasing rate of killing ability of EAS was decreased (along with ACC of solutions). Meanwhile, there was no obvious change in the nitrate concentration. The most effective mixed ratio EAS: hydroponic solution and exposure time for pathogens control were 2.5:500 with 30 min or 1.5:500 with 90 min. The mixed ratio of 1.5:500 with 90 min of exposure time were recommended because of its lesser changes on the properties of hydroponic solution. The mixed EAS - hydroponic solution did no negative effect to the growth of Brassica juncea in comparison with original hydroponic solution.
{"title":"Application of electrochemically activated solution to control pathogens of hydroponic solution","authors":"Nguyen Thi Thanh Hai, Truong Anh Dung, Nguyen Thi Quy","doi":"10.15625/2525-2518/16791","DOIUrl":"https://doi.org/10.15625/2525-2518/16791","url":null,"abstract":"In the current integration trend, high-tech agriculture is an inevitable direction for agricultural developing countries. In particular, hydroponics is a commonly used farming technique due to many advantages: no soil, space saving, no weeds, easy control of influencing factors, double yield. Hydroponic crop production systems are used worldwide to grow flowers, foliage, litter, and fruit and vegetable crops. Like other farming methods, hydroponics still has problems with pests and diseases that cause serious damage to the harvest that have not been completely resolved. One of the sources of pathogens is the hydroponic solution. Many methods to kill bacteria and fungi in hydroponic solutions have been studied. However, some methods gave low efficiency, others gave high efficiency but it caused secondary environmental pollution. Electrochemical activated solution (EAS), produced from dilute sodium chloride (NaCl) solution, has been wide known as a super disinfectant solution with high ability to kill most bacteria and fungi and is safe for humans. In this study we were forced on determine the ability to control pathogens in hydroponic solution of EAS, the effects of EAS on hydroponic solution properties and the growth of Brassica juncea in the mixed of EAS – hydroponic solution. Difference volume of EAS were added into hydroponic solutions and mixed for 30, 45, 60, 120 or 180 min. The most effective mixed solution (mixed ratio and time) was selected to apply to cultivate Brassica juncea. The results show that EAS has the ability to control pathogens in hydroponic solution very effectively, replacing other harmful chemicals. When increasing the volume EAS added (higher ACC of mixed solution) or the exposure time the TDS and ORP index of hydroponic solution were raised slightly while pH value was slightly dropped and the total coliform counts decreased significantly. The total coliform counts of mixed solutions reduced over the exposed time. However, the increasing rate of killing ability of EAS was decreased (along with ACC of solutions). Meanwhile, there was no obvious change in the nitrate concentration. The most effective mixed ratio EAS: hydroponic solution and exposure time for pathogens control were 2.5:500 with 30 min or 1.5:500 with 90 min. The mixed ratio of 1.5:500 with 90 min of exposure time were recommended because of its lesser changes on the properties of hydroponic solution. The mixed EAS - hydroponic solution did no negative effect to the growth of Brassica juncea in comparison with original hydroponic solution.","PeriodicalId":23553,"journal":{"name":"Vietnam Journal of Science and Technology","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84451759","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-17DOI: 10.15625/2525-2518/17417
Bùi Thị Thùy, Le Trung Thanh
We present a new method for image compression using the Haar wavelet transform (HWT) in all-optical domain. The proposed architecture is based on the optical Haar wavelet transform using only one 6×6 multimode interference (MMI) coupler. By locating the positions of input and output waveguides and optimizing design length of the MMI, the expected matrix of the Haar transform is obtained. The new hardware architecture is suitable for directly integrating with digital cameras for image processing. The processing of images therefore is at very high speed. Our method can also be applied to data compression in big data analytics. Our structure can provide a large fabrication tolerance which is compatible with the CMOS existing technology. Our simulations show that the length variation of ± 2 µm still keeps the output powers unchanged. We have simulate successfully the use of the proposed HWT to compress cameraman image with the compressed ratios of 20, 30, 50 % with MSE and PSNR from 0.1 - 0.3 and 62 – 67 dB, respectively.
{"title":"Image compression in all-optical domain using one 6×6 multimode interference coupler","authors":"Bùi Thị Thùy, Le Trung Thanh","doi":"10.15625/2525-2518/17417","DOIUrl":"https://doi.org/10.15625/2525-2518/17417","url":null,"abstract":"We present a new method for image compression using the Haar wavelet transform (HWT) in all-optical domain. The proposed architecture is based on the optical Haar wavelet transform using only one 6×6 multimode interference (MMI) coupler. By locating the positions of input and output waveguides and optimizing design length of the MMI, the expected matrix of the Haar transform is obtained. The new hardware architecture is suitable for directly integrating with digital cameras for image processing. The processing of images therefore is at very high speed. Our method can also be applied to data compression in big data analytics. Our structure can provide a large fabrication tolerance which is compatible with the CMOS existing technology. Our simulations show that the length variation of ± 2 µm still keeps the output powers unchanged. We have simulate successfully the use of the proposed HWT to compress cameraman image with the compressed ratios of 20, 30, 50 % with MSE and PSNR from 0.1 - 0.3 and 62 – 67 dB, respectively.\u0000 ","PeriodicalId":23553,"journal":{"name":"Vietnam Journal of Science and Technology","volume":"62 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84048567","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cell culture models more accurately would be of significant value to the medical field and pharmaceutical industry. To achieve this goal, microfluidic cell culture platforms are created and improved for modeling the native cell microenvironment because they can precisely reconstruct in vivo cellular behavior. In this study, a 3D low-cost microfluidic device is used to compare the difference between the static and dynamic environment in 3D cell culture. Cells were seeded in the microfluidic device, and to produce the fluidic flow, the pump was used with the set speed was 0.045ml/min. In 3D cell culture, the viability of cells was monitored by size growth of the spheroids for 7 days. All systems were designed and optimized without leakage of the medium. In the results, the 3D dynamic condition showed a faster increase in size than in the static condition. Overall, the study was prepared for microfluidic platforms with low-cost and simple settings. Moreover, the usage of 3D microfluidic to mimic in vivo returned favorable results that were expected for drug testing in the future.
{"title":"Development of novel, simple and low–cost microfluidic platform for supporting 3D dynamic cell culture","authors":"Nguyen Thanh Duong Nguyen, Thu Uyen Pham, Tran Dinh Thiet","doi":"10.15625/2525-2518/16735","DOIUrl":"https://doi.org/10.15625/2525-2518/16735","url":null,"abstract":"Cell culture models more accurately would be of significant value to the medical field and pharmaceutical industry. To achieve this goal, microfluidic cell culture platforms are created and improved for modeling the native cell microenvironment because they can precisely reconstruct in vivo cellular behavior. In this study, a 3D low-cost microfluidic device is used to compare the difference between the static and dynamic environment in 3D cell culture. Cells were seeded in the microfluidic device, and to produce the fluidic flow, the pump was used with the set speed was 0.045ml/min. In 3D cell culture, the viability of cells was monitored by size growth of the spheroids for 7 days. All systems were designed and optimized without leakage of the medium. In the results, the 3D dynamic condition showed a faster increase in size than in the static condition. Overall, the study was prepared for microfluidic platforms with low-cost and simple settings. Moreover, the usage of 3D microfluidic to mimic in vivo returned favorable results that were expected for drug testing in the future. \u0000 ","PeriodicalId":23553,"journal":{"name":"Vietnam Journal of Science and Technology","volume":"104 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80508366","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-17DOI: 10.15625/2525-2518/16615
Nguyen Thi Ngoc Linh, Le The Tam, Ngo Thanh Dung, Le Thi Thanh Tam, Ha Minh Nguyet, Nguyen Dinh Vinh, Bui Minh Quy, Nguyen Thi Hong Hoa, Nguyen Hoa Du, Le Trong Lu, Nguyen Trung Thành
In this work, Ag nanoparticles (NPs) were fabricated by thermal decomposition of silver nitrate in organic solvents in the presence of sodium oleate (SOA) and 1-octadecanol (OCD-ol). The effects of different solvents and concentrations of OCD-ol on the morphology and properties of the Ag nanomaterials were investigated in detail. The structural analysis of the Ag nanomaterials showed good crystallinity. The TEM images of the samples showed that with the change in the fabrication conditions, different sizes and shapes of Ag nanomaterials were formed. The surface plasmon resonance (SPR) properties of the Ag NPs were influenced by their size and shape. The as-synthesized Ag NPs have potential applications in biomedical, catalysis, or electronics.
{"title":"The size-and shape-controlled synthesis of silver nanoparticles by solvothermal method","authors":"Nguyen Thi Ngoc Linh, Le The Tam, Ngo Thanh Dung, Le Thi Thanh Tam, Ha Minh Nguyet, Nguyen Dinh Vinh, Bui Minh Quy, Nguyen Thi Hong Hoa, Nguyen Hoa Du, Le Trong Lu, Nguyen Trung Thành","doi":"10.15625/2525-2518/16615","DOIUrl":"https://doi.org/10.15625/2525-2518/16615","url":null,"abstract":"In this work, Ag nanoparticles (NPs) were fabricated by thermal decomposition of silver nitrate in organic solvents in the presence of sodium oleate (SOA) and 1-octadecanol (OCD-ol). The effects of different solvents and concentrations of OCD-ol on the morphology and properties of the Ag nanomaterials were investigated in detail. The structural analysis of the Ag nanomaterials showed good crystallinity. The TEM images of the samples showed that with the change in the fabrication conditions, different sizes and shapes of Ag nanomaterials were formed. The surface plasmon resonance (SPR) properties of the Ag NPs were influenced by their size and shape. The as-synthesized Ag NPs have potential applications in biomedical, catalysis, or electronics.","PeriodicalId":23553,"journal":{"name":"Vietnam Journal of Science and Technology","volume":"168-169 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73212766","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-17DOI: 10.15625/2525-2518/17308
N. T. Phuong, H. Nguyen, Dao Thanh Duong, Trinh Bich Ngoc, Le Phuong Thu, Dinh Thi Mai Thanh, Nguyen Van Dong
Economic development in many developing countries is leading to a significant increase in atmospheric CO2 in recent decades, exacerbating global climate change. One of the solutions being vigorously researched is the use of cheap and environmentally friendly CO2 adsorbents. In this study, solid residues from gasification of bagasse, and pyrolysis of macadamia nut shells were used for CO2 adsorption. The N2 adsorption/desorption results showed that the post-gasification residue was much more porous compared to the post-pyrolysis residue. The CO2 adsorption experiments were carried out in laboratory conditions (100 % CO2, 25 °C) and flue gas conditions (15 % CO2, 40 °C). The bagasse residue achieved a high and stable CO2 adsorption value at 2.3 mmol/g, 2.5 times more than that of macadamia nut shells residue. This result showed that residues from thermal conversion processes could be re-used as cheap and environmentally friendly materials for CO2 capture.
{"title":"Potential use of residues from thermal conversion processes for CO2 capture","authors":"N. T. Phuong, H. Nguyen, Dao Thanh Duong, Trinh Bich Ngoc, Le Phuong Thu, Dinh Thi Mai Thanh, Nguyen Van Dong","doi":"10.15625/2525-2518/17308","DOIUrl":"https://doi.org/10.15625/2525-2518/17308","url":null,"abstract":"Economic development in many developing countries is leading to a significant increase in atmospheric CO2 in recent decades, exacerbating global climate change. One of the solutions being vigorously researched is the use of cheap and environmentally friendly CO2 adsorbents. In this study, solid residues from gasification of bagasse, and pyrolysis of macadamia nut shells were used for CO2 adsorption. The N2 adsorption/desorption results showed that the post-gasification residue was much more porous compared to the post-pyrolysis residue. The CO2 adsorption experiments were carried out in laboratory conditions (100 % CO2, 25 °C) and flue gas conditions (15 % CO2, 40 °C). The bagasse residue achieved a high and stable CO2 adsorption value at 2.3 mmol/g, 2.5 times more than that of macadamia nut shells residue. This result showed that residues from thermal conversion processes could be re-used as cheap and environmentally friendly materials for CO2 capture.","PeriodicalId":23553,"journal":{"name":"Vietnam Journal of Science and Technology","volume":"28 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90371959","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-17DOI: 10.15625/2525-2518/16318
Chau Thanh Hien, Dang Minh Nhat, Mac Thi Ha Thanh
This paper presents the result of study on the effect of modifying conditions on properties and structure of tuna skin gelatin by using green tea polyphenols. The results showed that gelatin modified by green tea polyphenols changed its gel strength, degree of cross-linking, molecular weight and gel structure. The appropriate parameters to modify gelatin by using green tea polyphenols which indicated the best mechanical properties were determined as follows: temperature of 40oC in 40 minutes, polyphenol content of 20 mg/g gelatin and gelatin solution of 20%. As a result, modified gelatin showed a decrease in solubility, an increase in cross-linking degree (16.7%), molecular weight (55÷72 kDa) as well as a larger protein structure in comparison with the natural gelatin. The IR spectrograph of the modified gelatin did not show any evidence of forming new functional groups, only an apparent change in the absorption of infrared spectroscopy at the peak of the amide B region was found. The dried modified gelatin became insoluble in hot water.
{"title":"Modification of gelatin from tuna skins by green tea polyphenols","authors":"Chau Thanh Hien, Dang Minh Nhat, Mac Thi Ha Thanh","doi":"10.15625/2525-2518/16318","DOIUrl":"https://doi.org/10.15625/2525-2518/16318","url":null,"abstract":"This paper presents the result of study on the effect of modifying conditions on properties and structure of tuna skin gelatin by using green tea polyphenols. The results showed that gelatin modified by green tea polyphenols changed its gel strength, degree of cross-linking, molecular weight and gel structure. The appropriate parameters to modify gelatin by using green tea polyphenols which indicated the best mechanical properties were determined as follows: temperature of 40oC in 40 minutes, polyphenol content of 20 mg/g gelatin and gelatin solution of 20%. As a result, modified gelatin showed a decrease in solubility, an increase in cross-linking degree (16.7%), molecular weight (55÷72 kDa) as well as a larger protein structure in comparison with the natural gelatin. The IR spectrograph of the modified gelatin did not show any evidence of forming new functional groups, only an apparent change in the absorption of infrared spectroscopy at the peak of the amide B region was found. The dried modified gelatin became insoluble in hot water.","PeriodicalId":23553,"journal":{"name":"Vietnam Journal of Science and Technology","volume":"2019 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87856514","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-17DOI: 10.15625/2525-2518/18032
N. Phuc, Do Hung Manh, Pham Hong Nam
Electromagnetic heating (EMH) is a process of adsorbing electromagnetic wave energy by a material and converting it into heat. Nanomaterials can serve as novel susceptors in EMH due to the fine size that made them become heat sources from inside, as well as because of new heating mechanisms such as Neel relaxation by magnetic nanoparticles (MNPs) and localized surface plasmon resonance by metallic nanostructures. This review firstly introduces general theoretical & experimental aspects of the alternating electric field (AEF)- and magnetic field (AMF)-stimulated heating. Next, attempts to fabricate MNPs and photothermal nanoparticles (PNPs) of improved heating efficiencies have been reviewed and those with the highest specific loss power have been summarized. Finally, potential applications, including cancer treatment using AMF@MNP hyperthermia and AEF@PNP hyperthermia, AMF@MNP- and AEF@PNP- triggered drug release, as well as nanocomposite processing were particularly highlighted. Besides, other exotic applications such as toxic solvent desorption from adsorbent materials, thermophoresis in precise membrane melting as well as optical signal processing in heat-assisted magnetic memory technology were also outlined. The various applications were attempted to represent into 2 groups: biomedicine, and materials processing; which are composed of localized/targeted and volumetric heating type.
{"title":"Electromagnetic heating using nanomaterials and various potentials applications","authors":"N. Phuc, Do Hung Manh, Pham Hong Nam","doi":"10.15625/2525-2518/18032","DOIUrl":"https://doi.org/10.15625/2525-2518/18032","url":null,"abstract":"Electromagnetic heating (EMH) is a process of adsorbing electromagnetic wave energy by a material and converting it into heat. Nanomaterials can serve as novel susceptors in EMH due to the fine size that made them become heat sources from inside, as well as because of new heating mechanisms such as Neel relaxation by magnetic nanoparticles (MNPs) and localized surface plasmon resonance by metallic nanostructures. This review firstly introduces general theoretical & experimental aspects of the alternating electric field (AEF)- and magnetic field (AMF)-stimulated heating. Next, attempts to fabricate MNPs and photothermal nanoparticles (PNPs) of improved heating efficiencies have been reviewed and those with the highest specific loss power have been summarized. Finally, potential applications, including cancer treatment using AMF@MNP hyperthermia and AEF@PNP hyperthermia, AMF@MNP- and AEF@PNP- triggered drug release, as well as nanocomposite processing were particularly highlighted. Besides, other exotic applications such as toxic solvent desorption from adsorbent materials, thermophoresis in precise membrane melting as well as optical signal processing in heat-assisted magnetic memory technology were also outlined. The various applications were attempted to represent into 2 groups: biomedicine, and materials processing; which are composed of localized/targeted and volumetric heating type.","PeriodicalId":23553,"journal":{"name":"Vietnam Journal of Science and Technology","volume":"44 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80706010","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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